[brucek]

So....can anyone recommend a USB mic and is it even recommended?

No, REW won't operate with a USB mic. For laptops, most people require an external USB soundcard that has a line-in and a line-out, or a line-out and a mic preamp for condenser microphones.

brucek

 

[brucek]

use my laptops mic input connector for REW

No, the mic-in jacks on laptops are not suitable for use with REW.

brucek

 

[brucek]

So the measurement quality depends only on the mic you use.

How are you able to do a soundcard calibration when using USB as the input?

brucek

 

[brucek]

Aren't these flat enough?
What's the difference?

Use any mic you wish as long as you have a mic calibration file that REW can use.

brucek